Altitude performance characteristics of the J47-25 turbojet engine :data presentation

Renas, Paul E., Jansen, Emmert T.

The altitude performance of the J47-25 turbojet engine operating with a fixed-area exhaust nozzle was determined over a range of engine-inlet Reynolds numbers corresponding to altitudes from 18,000 to 54,000 feet and flight Mach numbers from 0.50 to 1.10. Reducing the engine-inlet Reynolds number resulted in a reduction in corrected air flow but had essentially no effect on corrected exhaust-gas total temperature, corrected fuel flow, and engine pumping characteristics for a range of Reynolds number indices from 0.80 to 0.30. The corrected jet thrust parameter generalized throughout the range of engine-inlet Reynolds numbers investigated. At a given corrected engine speed with critical pressure ratio existing in the exhaust nozzle, increasing the engine-inlet ram-pressure ratio from 1.0 to 1.25 decreased the corrected exhaust-gas temperature. Further increases in ram-pressure ratio had no effect on the exhaust-gas temperature.

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